Apparatus for Concentrating Wastewater and for Creating Brines

ABSTRACT

A liquid concentrator system includes a concentrator section having a gas inlet, a gas outlet, and a mixing corridor disposed between the gas inlet and the gas outlet. A liquid inlet is disposed in the mixing corridor between the gas inlet and a narrowed portion. A demister is disposed downstream of the concentrator section. The demister includes a liquid collector to remove liquid from gas flowing through the demister, and a reservoir that collects the removed liquid. A re-circulating circuit is disposed between reservoir and the mixing corridor to transport liquid within the reservoir to the mixing corridor, and a secondary re-circulating circuit includes a settling tank to separate saturated liquid and suspended solids. A custom brine mixing device is operatively coupled to the settling tank.

FIELD OF THE DISCLOSURE

This application relates generally to liquid concentrators, and morespecifically to cost-effective wastewater concentrators that can beeasily connected to and use sources of waste heat, whether in a smallerscale, compact, and/or portable setting, in a larger scale, fixedinstallation, or otherwise. The concentrators can be used to concentrateliquid wastewater streams and to mix custom brines with targeted weightsthat may be used in the drilling industry as drilling muds.

BACKGROUND

Concentration of volatile or other substances can be an effective formof treatment or pretreatment for a broad variety of wastewater streamsand may be carried out within various types of commercial processingsystems. At high levels of concentration, many wastewater streams may bereduced to residual material in the form of slurries containing highlevels of dissolved and suspended solids. Such concentrated residual maybe readily solidified by conventional techniques for disposal withinlandfills or, as applicable, delivered to downstream processes forfurther treatment prior to final disposal. Concentrating wastewater cangreatly reduce freight costs and required storage capacity and may bebeneficial in downstream processes where materials are recovered fromthe wastewater.

An important measure of the effectiveness of a wastewater concentrationprocess is the volume of residual produced in proportion to the volumeof wastewater entering the process. In particular, low ratios ofresidual volume to feed volume (high levels of concentration) are themost desirable. Where the wastewater contains dissolved and/or suspendednon-volatile matter, the volume reduction that may be achieved in aparticular concentration process that relies on evaporation of volatilesis, to a great extent, limited by the method chosen to transfer heat tothe process fluid.

Conventional processes that affect concentration by evaporation of waterand other volatile substances may be classified as direct or indirectheat transfer systems depending upon the method employed to transferheat to the liquid undergoing concentration (the process fluid).Indirect heat transfer devices generally include jacketed vessels thatcontain the process fluid, or tubular, plate, bayonet, or coil type heatexchangers that are immersed within the process fluid. Mediums such assteam or hot oil are passed through the jackets or heat exchangers inorder to transfer the heat required for evaporation. Direct heattransfer devices implement processes where the heating medium is broughtinto direct contact with the process fluid, which occurs in, forexample, submerged combustion gas systems.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a liquid concentrator.

FIG. 2 is a front perspective view of an evaporator/concentrator portionof the liquid concentrator of FIG. 1.

FIG. 3 is a schematic view of a control system for the liquidconcentrator of FIG. 1.

FIG. 4 is a close up schematic view of the settling tank of the liquidconcentrator of FIG. 1 and of a custom brine mixing system.

DETAILED DESCRIPTION

The liquid concentrator described herein may be used to concentrate awide variety of wastewater streams, such as waste water from industry,runoff water from natural disasters (floods, hurricanes), refinerycaustic, leachate such as landfill leachate (e.g., from power plants),flowback water from completion of natural gas wells, produced water fromoperation of natural gas wells, flue gas desulfurization (FGD) waterfrom power plants (e.g., from an air quality control system (AQCS)process for power plant flue gas or other sulfur dioxide-containinggas), etc. The liquid concentrator is practical, energy efficient,reliable, and cost-effective. The liquid concentrator described hereinhas all of these desirable characteristics and provides significantadvantages over conventional wastewater concentrators, especially whenthe goal is to manage a broad variety of wastewater streams.

Moreover, the concentrator may be largely fabricated from highlycorrosion resistant, yet low cost materials such as fiberglass and/orother engineered plastics. This is due, in part, to the fact that thedisclosed concentrator is designed to operate under minimal differentialpressure. For example, a differential pressure generally in the range ofonly 10 to 30 inches water column is required. Also, because thegas-liquid contact zones of the concentration processes generate highturbulence within narrowed (compact) passages at or directly after theventuri section of the flow path, the overall design is very compact ascompared to conventional concentrators where the gas liquid contactoccurs in large process vessels. As a result, the amount of high alloymetals required for the concentrator is quite minimal. Also, becausethese high alloy parts are small and can be readily replaced in a shortperiod of time with minimal labor, fabrication costs may be cut to aneven higher degree by designing some or all of these parts to be wearitems manufactured from lesser quality alloys that are to be replaced atperiodic intervals. If desired, these lesser quality alloys (e.g.,carbon steel) may be coated with corrosion and/or erosion resistantliners, such as engineered plastics including elastomeric polymers, toextend the useful life of such components. Likewise, pumps may beprovided with corrosion and/or erosion resistant liners to extend thelife of the pumps, thus further reducing maintenance and replacementcosts.

The liquid concentrator provides direct contact of the liquid to beconcentrated and the hot gas, effecting highly turbulent heat exchangeand mass transfer between hot gas and the liquid, e.g., wastewater,undergoing concentration. Moreover, the concentrator employs highlycompact gas-liquid contact zones, making it minimal in size as comparedto known concentrators. The direct contact heat exchange featurepromotes high energy efficiency and eliminates the need for solidsurface heat exchangers as used in conventional, indirect heat transferconcentrators. Further, the compact gas-liquid contact zone eliminatesthe bulky process vessels used in both conventional indirect and directheat exchange concentrators. These features allow the concentrator to bemanufactured using comparatively low cost fabrication techniques andwith reduced weight as compared to conventional concentrators. Both ofthese factors favor portability and cost-effectiveness. Thus, the liquidconcentrator is more compact and lighter in weight than conventionalconcentrators, which make it ideal for use as a portable unit.Additionally, the liquid concentrator is less prone to fouling andblockages due to the direct contact heat exchange operation and the lackof solid heat exchanger surfaces. The liquid concentrator can alsoprocess liquids with significant amounts of suspended solids because ofthe direct contact heat exchange. As a result, high levels ofconcentration of the process fluids may be achieved without need forfrequent cleaning of the concentrator.

More specifically, in liquid concentrators that employ indirect heattransfer, the heat exchangers are prone to fouling and are subject toaccelerated effects of corrosion at the normal operating temperatures ofthe hot heat transfer medium that is circulated within them (steam orother hot fluid). Each of these factors places significant limits on thedurability and/or costs of building conventional indirectly heatedconcentrators, and on how long they may be operated before it isnecessary to shut down and clean or repair the heat exchangers. Byeliminating the bulky process vessels, the weight of the liquidconcentrators and both the initial costs and the replacement costs forhigh alloy components are greatly reduced. Moreover, due to thetemperature difference between the gas and liquid, the relatively smallvolume of liquid contained within the system, the relatively largeinterfacial area between the liquid and the gas, and the reducedrelative humidity of the gas prior to mixing with the liquid, theconcentrator approaches the adiabatic saturation temperature for theparticular gas/liquid mixture, which is typically in the range of about140 degrees Fahrenheit to about 190 degrees Fahrenheit. This mildoperating temperature beyond the evaporation zone is a factor thatallows favorable use of low-cost yet highly corrosion-resistantengineered materials of construction throughout the remaining processzones of the concentrator (i.e., which reduces capital costs compared toother wastewater concentrators). The concentrator can be classified as a“low momentum” concentrator, which refers to the high rate at whichdischarge fluid from the concentrator is recirculated back to the inletof the evaporation zone, which is typically in the range of 10:1 to 15:1times the feed rate of wastewater into the concentrator. Multiple passesof the liquid phase add stability to the process by maintaining a highratio of wastewater undergoing concentration to hot inlet gas volumewithin the concentrator. This feature prevents drying of small liquiddroplets (e.g., at the low end of a droplet particle size distributioncharacterizing the droplet population in the concentrator) created inthe highly turbulent evaporation zone by maintaining a high ratio ofliquid to inlet hot gas volume, which causes rapid saturation of the gasphase at close to the adiabatic saturation temperature for thecontinuous gas phase and discontinuous liquid phase mixture. Thisapproach to thermodynamic equilibrium effectively quenches the drivingforce for the gaseous stream to absorb additional water and thusprevents complete drying of wastewater droplets which would lead totroublesome buildup of solids upon wetted walls of the processingequipment causing need for frequent and often arduous cleaning cycles.Thus, rather than precisely balancing the injected wastewater feed atthe precise level of total solids present in the wastewater at a givenpoint in time, the high recirculation allows the process to self-adjustto variances in the feed wastewater composition without causing processdisturbances. Further, this feature stabilizes the concentration processwhenever there is need to precisely add reagents to the feed wastewater(e.g., controlling pH, to prevent foaming or sequestering componentswithin the concentrated phase).

Moreover, the concentrator is designed to operate under negativepressure, a feature that greatly enhances the ability to use a verybroad range of fuel or waste heat sources as an energy source to affectevaporation. In fact, due to the draft nature of these systems,pressurized or non-pressurized burners may be used to heat and supplythe gas used in the concentrator. Further, the simplicity andreliability of the concentrator is enhanced by the minimal number ofmoving parts and wear parts that are required. In general, only twopumps and a single induced draft fan are required for the concentratorwhen it is configured to operate on waste heat such as stack gases fromengines (e.g., generators or vehicle engines), turbines, industrialprocess stacks, gas compressor systems, and exhaust stacks, such aslandfill gas exhaust stacks, flue gas exhaust stacks, or otherwise.These features provide significant advantages that reflect favorably onthe versatility and the costs of buying, operating and maintaining theconcentrator.

The concentrator may be run in a transient start up condition, or in asteady state condition. During the startup condition, the demister sumpis first filled with wastewater feed. As the level of wastewater feedapproaches the normal operating level of the sump, a re-circulatingcircuit is then established between a lower inlet of the evaporationzone and the outlet of the sump. Once recirculation has beenestablished, wastewater feed to an upper inlet to the evaporation zoneis established. Once both recirculating and wastewater feed flows to thelower and upper inlets of the evaporation zone have been established,flow of hot gas to the system is established. During initial processing,the combined fresh wastewater introduced into the upper wastewater inletand recirculated wastewater introduced to the lower recirculated inletis at least partially evaporated in a narrowed portion of a concentratorsection and is deposited in the demister sump in a more concentratedform than the fresh wastewater. Over time, the wastewater in thedemister sump and the re-circulating circuit approaches a desired levelof concentration. At this point, the concentrator may be run in acontinuous mode where the amount of total solids drawn off from anextraction port equals the amount of total solids introduced in freshwastewater through the inlet. The balance of total solids generallyincludes the contribution from total dissolved solids and totalsuspended solids, for example where the fresh wastewater feed mightcontain mostly or only dissolved solids, and the concentrated streamdrawn from the extraction port might contain a higher fraction ofsuspended solids having precipitated from dissolved solids during theconcentration process. Likewise, the amount of water evaporated withinthe concentrator is replaced by an equal amount of water in the freshwastewater. Thus, conditions within the concentrator approach theadiabatic saturation point of the mixture of heated gas and wastewaterand continuous operation at a desired equilibrium rate of water removalis established while evaporated water vapor exits the concentrator onthe discharge side of the induced draft fan.

Generally, a liquid concentrator may include a gas inlet, a gas exit,and a flow corridor connecting the gas inlet to the gas exit. The flowcorridor may include a narrowed portion that accelerates the flow of gasthrough the flow corridor creating turbulent flow within the flowcorridor at or near this location. The narrowed portion may be formed bya venturi device. A liquid inlet injects a liquid to be concentrated(via evaporation) into a liquid concentration chamber in the flowcorridor at a point upstream of the narrowed portion, and the injectedliquid joins with the gas flow in the flow corridor. The liquid inletmay include one or more replaceable nozzles for spraying the liquid intothe flow corridor. The inlet, whether or not equipped with a nozzle, mayintroduce the liquid in any direction from perpendicular to parallel tothe gas flow as the gas moves through the flow corridor. A baffle mayalso be located near the liquid inlet such that liquid introduced fromthe liquid inlet impinges on the baffle and disperses into the flowcorridor in small droplets.

As the gas and liquid flow through the narrowed portion, the venturiprinciple creates an accelerated and turbulent flow that thoroughlymixes the gas and liquid in the flow corridor at and after the locationof the inlet. This acceleration through the narrowed portion createsshearing forces between the gas flow and the liquid droplets, andbetween the liquid droplets and the walls of the narrowed portion,resulting in the formation of very fine liquid droplets entrained in thegas, thus increasing the interfacial surface area between the liquiddroplets and the gas and effecting rapid mass and heat transfer betweenthe gas and the liquid droplets. The liquid exits the narrowed portionas very fine droplets regardless of the geometric shape of the liquidflowing into the narrowed portion (e.g., the liquid may flow into thenarrowed portion as a sheet of liquid). As a result of the turbulentmixing and shearing forces, a portion of the liquid rapidly vaporizesand becomes part of the gas stream. As the gas-liquid mixture movesthrough the narrowed portion, the direction and/or velocity of thegas/liquid mixture may be changed by an adjustable flow restriction,such as a venturi plate, which is generally used to create a largepressure difference in the flow corridor upstream and downstream of theventuri plate. The venturi plate may be adjustable to control the sizeand/or shape of the narrowed portion and may be manufactured from acorrosion resistant material including a high alloy metal such as thosemanufactured under the trade names of HASTELLOY, INCONEL, and MONEL.

After leaving the narrowed portion, the gas-liquid mixture passesthrough a demister (also referred to as fluid scrubbers or entrainmentseparators) coupled to the gas exit. The demister removes entrainedliquid droplets from the gas stream. The demister includes a gas-flowpassage. The removed liquid collects in a liquid collector or sumpmounted beneath the gas-flow passage, the sump may also include areservoir for holding the removed liquid. A pump fluidly coupled to thesump and/or reservoir moves a portion of the liquid through are-circulating circuit back to the liquid inlet and/or flow corridor. Inthis manner, the liquid may be reduced through evaporation to a desiredconcentration. Fresh or new liquid to be concentrated is input to there-circulating circuit through a liquid inlet. This new liquid mayinstead be injected directly into the flow corridor upstream of theventuri plate. The rate of fresh liquid input into the re-circulatingcircuit may be equal to the rate of evaporation of the liquid as thegas-liquid mixture flows through the flow corridor plus the rate ofliquid extracted through a concentrated fluid extraction port located inor near the reservoir in the sump. The concentrated fluid extractedthrough port can be fed to one or more downstream unit operations (e.g.,solid/liquid separation, further processing in astabilization/solidification (S/S) process, etc.). The ratio ofre-circulated liquid to fresh liquid may generally be in the range ofapproximately 1:1 to approximately 100:1, and is usually in the range ofapproximately 5:1 to approximately 25:1. For example, if there-circulating circuit circulates fluid at approximately 10 gal/min,fresh or new liquid may be introduced at a rate of approximately 1gal/min (i.e., a 10:1 ratio). A portion of the liquid may be drawn offthrough the extraction port when the liquid in the re-circulatingcircuit reaches a desired concentration. The re-circulating circuit addsstability to the evaporation process ensuring that enough moisture isalways present in the flow corridor to prevent the liquid from beingcompletely evaporated and/or preventing the formation of dryparticulate.

After passing through the demister the gas stream passes through aninduction fan that draws the gas through the flow corridor and demistergas-flow corridor under negative pressure. Of course, the concentratorcould operate under positive pressure produced by a blower prior to theliquid inlet. Finally, the gas is vented to the atmosphere or directedfor further processing such as for return for collection of clean waterby means of condensation through the gas exit.

The concentrator may include a pre-treatment system for treating theliquid to be concentrated, which may be a wastewater feed. For example,an air stripper may be used as a pre-treatment system to removesubstances that may produce foul odors or be regulated as airpollutants. In this case, the air stripper may be any conventional typeof air stripper or may be a further concentrator of the type describedherein, which may be used in series as the air stripper. Thepre-treatment system may, if desired, heat the liquid to be concentratedusing any desired heating technique. Additionally, the gas and/orwastewater feed circulating through the concentrator may be pre-heatedin a pre-heater. Pre-heating may be used to enhance the rate ofevaporation and thus the rate of concentration of the liquid. The gasand/or wastewater feed may be pre-heated through combustion of renewablefuels such as wood chips, bio-gas, methane, or any other type ofrenewable fuel or any combination of renewable fuels, fossil fuels andwaste heat. Furthermore, the gas and/or wastewater may be pre-heatedthrough the use of waste heat generated in a landfill flare or stack.Also, waste heat from an engine, such as an internal combustion engine,or a gas turbine, may be used to pre-heat the gas and/or wastewaterfeed. Still further, natural gas may be used as a source of waste heat,the natural gas may be supplied directly from a natural gas well head inan unrefined condition either immediately after completion of thenatural gas well before the gas flow has stabilized or after the gasflow has stabilized in a more steady state natural gas well. Optionally,the natural gas may be refined before being combusted in the flare.Additionally, the gas streams ejected from the gas exit of theconcentrator may be transferred into a flare or other post treatmentdevice which treats the gas before releasing the gas to the atmosphere.

FIG. 1 illustrates one particular embodiment of a (compact) liquidconcentrator 110, which can be connected to a source of waste heat inthe form of a gas flare exhaust stack 130. Generally speaking, thecompact liquid concentrator 110 of FIG. 1 operates to concentratewastewater, such as flowback or produced water from a natural gas well,using exhaust or waste heat created by burning natural gas in the gasflare exhaust stack 130. Typically, the heated gas exiting from theexhaust stack ranges from about 300 or 400 to 500, 600, or 700 degreesFahrenheit, although higher temperatures are possible, such as up to800, 1000, 1200, 1500, or 1800 degrees Fahrenheit.

As illustrated in FIG. 1, the compact liquid concentrator 110 generallyincludes an inlet assembly 119, a concentrator assembly 120 (shown inmore detail in FIG. 2), a demister or fluid scrubber 122, and an outlet(or exhaust) section 124. For example, the concentrator 110 inletassembly 119 can be interfaced with the gas flare exhaust stack 130 viaductwork and a butterfly control valve (or similar; not shown) thatisolates the concentrator 110 when closed and allows for hot flue gas tobe drawn in when open. Similarly, a bypass valve (not shown) can beincluded to operate in the opposite fashion. When the concentrator 110shuts down, the bypass valve may open to equilibrate the concentrator110 to atmosphere conditions and help purge the concentrator 110 of anyremnant flue gases.

The liquid concentrator assembly 120 includes a lead-in section 156having a reduced cross-section at the top end thereof which mates to thebottom of the piping section of the inlet assembly 119 (e.g., deliveringa hot gas such as exhaust gas from the gas flare exhaust stack 130) to aquencher 159 of the concentrator assembly 120. The concentrator assembly120 also includes a first fluid inlet 160, which injects new oruntreated liquid to be concentrated, such as flowback or produced waterfrom a natural gas well, into the interior of the quencher 159. Whilenot shown in FIG. 1, the inlet 160 may include a coarse sprayer with alarge nozzle for spraying the untreated liquid into the quencher 159.Because the liquid being sprayed into the quencher 159 at this point inthe system is not yet concentrated, and thus has large amount of watertherein, and because the sprayer is a coarse sprayer, the sprayer nozzleis not subject to fouling or being clogged by the small particles withinthe liquid. The quencher 159 operates to quickly reduce the temperatureof the gas stream (e.g., from about 300 or 400 to 500, 600, 700, or 900degrees Fahrenheit to less than 200 degrees Fahrenheit) while performinga high degree of evaporation on the liquid injected at the inlet 160. Ifdesired, but not specifically shown in FIG. 1, a temperature sensor maybe located at or near the exit of the inlet assembly 119 or in thequencher 159 and may be used to control the position of an ambient airvalve (not shown) in the inlet assembly 119 to thereby control thetemperature of the gas present at the inlet of the concentrator assembly120.

As shown in FIGS. 1 and 2, the quencher 159 is connected to a liquidinjection chamber which is connected to narrowed portion or venturisection 162 which has a narrowed cross section with respect to thequencher 159 and which has a venturi plate 163 (shown in dotted line)disposed therein. The venturi plate 163 creates a narrow passage throughthe venturi section 162, which creates a large pressure drop between theentrance and the exit of the venturi section 162. This large pressuredrop causes turbulent gas flow and shearing forces within the quencher159 and the top or entrance of the venturi section 162, and causes ahigh rate of gas flow out of the venturi section 162, both of which leadto thorough mixing of the gas and liquid in the venturi section 162. Theposition of the venturi plate 163 may be controlled with a manualcontrol rod 165 (shown in FIG. 2) connected to the pivot point of theplate 163, or via an automatic positioner that may be driven by anelectric motor or pneumatic cylinder (not shown in FIG. 2).

A re-circulating pipe 166 extends around opposite sides of the entranceof the venturi section 162 and operates to inject partially concentrated(i.e., re-circulated) liquid into the venturi section 162 to be furtherconcentrated and/or to prevent the formation of dry particulate withinthe concentrator assembly 120 through multiple fluid entrances locatedon one or more sides of the flow corridor. While not explicitly shown inFIGS. 1 and 2, a number of pipes, such as three pipes of, for example, ½inch diameter, may extend from each of the opposites legs of the pipe166 partially surrounding the venturi section 162, and through the wallsand into the interior of the venturi section 162. Because the liquidbeing ejected into the concentrator 110 at this point is re-circulatedliquid, and is thus either partially concentrated or being maintained ata particular equilibrium concentration and more prone to plug a spraynozzle than the less concentrated liquid injected at the inlet 160, thisliquid may be directly injected without a sprayer so as to preventclogging. However, if desired, a baffle in the form of a flat plate maybe disposed in front of each of the openings of the ½ diameter pipes tocause the liquid being injected at this point in the system to hit thebaffle and disperse into the concentrator assembly 120 as smallerdroplets. In any event, the configuration of this re-circulating systemdistributes or disperses the re-circulating liquid better within the gasstream flowing through the concentrator assembly 120.

The combined hot gas and liquid flows in a turbulent manner through theventuri section 162. As noted above, the venturi section 162, which hasa moveable venturi plate 163 disposed across the width of theconcentrator assembly 120, causes turbulent flow and complete mixture ofthe liquid and gas, causing rapid evaporation of the discontinuousliquid phase into the continuous gas phase. Because the mixing actioncaused by the venturi section 162 provides a high degree of evaporation,the gas cools substantially in the concentrator assembly 120, and exitsthe venturi section 162 into a flooded elbow 164 at high rates of speed.In fact, the temperature of the gas-liquid mixture at this point may beabout 160 degrees Fahrenheit.

A weir arrangement (not shown) within the bottom of the flooded elbow164 may maintain a constant level of partially or fully concentratedre-circulated liquid disposed therein. Droplets of re-circulated liquidthat are entrained in the gas phase as the gas-liquid mixture exits theventuri section 162 at high rates of speed are thrown outward onto thesurface of the re-circulated liquid held within the bottom of theflooded elbow 164 by centrifugal force generated when the gas-liquidmixture is forced to turn 90 degrees to flow into the fluid scrubber122. Significant numbers of liquid droplets entrained within the gasphase that impinge on the surface of the re-circulated liquid held inthe bottom of the flooded elbow 164 coalesce and join with there-circulated liquid thereby increasing the volume of re-circulatedliquid in the bottom of the flooded elbow 164 causing an equal amount ofthe re-circulated liquid to overflow the weir arrangement and flow bygravity into the sump 172 at the bottom of the fluid scrubber 122. Thus,interaction of the gas-liquid stream with the liquid within the floodedelbow 164 removes liquid droplets from the gas-liquid stream, and alsoprevents suspended particles within the gas-liquid stream from hittingthe bottom of the flooded elbow 164 at high velocities, therebypreventing erosion of the metal that forms the portions of side wallslocated beneath the level of the weir arrangement and the bottom of theflooded elbow 164.

After leaving the flooded elbow 164, the gas-liquid stream in whichevaporated liquid and some liquid and other particles still exist, flowsthrough the fluid scrubber 122 which is, in this case, a cross-flowfluid scrubber. The fluid scrubber 122 includes various screens orfilters which serve to remove entrained liquids and other particles fromthe gas-liquid stream. In one particular example, the cross flowscrubber 122 may include an initial coarse impingement baffle 169 at theinput thereof, which is designed to remove liquid droplets in the rangeof 50 to 100 microns in size or higher. Thereafter, two removablefilters in the form of chevrons 170 are disposed across the fluid paththrough the fluid scrubber 122, and the chevrons 170 may beprogressively sized or configured to remove liquid droplets of smallerand smaller sizes, such as 20-30 microns and less than 10 microns. Ofcourse, more or fewer filters or chevrons could be used.

Liquid captured by the filters 169 and 170 and the overflow weirarrangement within the bottom of the flooded elbow 164 drain by gravityinto a reservoir or sump 172 located at the bottom of the fluid scrubber122. The sump 172, which may hold, for example approximately 200 gallonsof liquid, thereby collects concentrated fluid containing dissolved andsuspended solids removed from the gas-liquid stream and operates as areservoir for a source of re-circulating concentrated liquid back to theconcentrator assembly 120 to be further treated and/or to prevent theformation of dry particulate within the concentrator assembly 120. Inone embodiment, the sump 172 may include a sloped V-shaped bottom 171having a V-shaped groove 175 extending from the back of the fluidscrubber 122 (furthest away from the flooded elbow 164) to the front ofthe fluid scrubber 122 (closest to the flooded elbow 164), wherein theV-shaped groove 175 is sloped such that the bottom of the V-shapedgroove 175 is lower at the end of the fluid scrubber 122 nearest theflooded elbow 164 than at an end farther away from the flooded elbow164. In other words, the V-shaped bottom 171 may be sloped with thelowest point of the V-shaped bottom 171 proximate the exit port 173and/or the pump 182. Additionally, a washing circuit 177 (FIG. 3) maypump concentrated fluid from the sump 172 to a sprayer 179 within thecross flow scrubber 122, the sprayer 179 being aimed to spray liquid atthe V-shaped bottom 171. Alternatively, the sprayer 179 may sprayun-concentrated liquid or clean water at the V-shaped bottom 171. Thesprayer 179 may periodically or constantly spray liquid onto the surfaceof the V-shaped bottom 171 to wash solids and prevent solid buildup onthe V-shaped bottom 171 or at the exit port 173 and/or the pump 182. Asa result of this V-shaped sloped bottom 171 and washing circuit 177,liquid collecting in the sump 172 is continuously agitated and renewed,thereby maintaining a relatively constant consistency and maintainingsolids in suspension. If desired, the spraying circuit 177 may be aseparate circuit using a separate pump with, for example, an inletinside of the sump 172, or may use a pump 182 associated with aconcentrated liquid re-circulating circuit described below to sprayconcentrated fluid from the sump 172 onto the V-shaped bottom 171.

As illustrated in FIG. 1, a return line 180, as well as a pump 182,operate to re-circulate fluid removed from the gas-liquid stream fromthe sump 172 back to the concentrator 120 and thereby complete a fluidor liquid re-circulating circuit. Likewise, a pump 184 may be providedwithin an input line 186 to pump new or untreated liquid, such asflowback or produced water from a natural gas well, or otherwise, to theinput 160 of the concentrator assembly 120. Also, one or more sprayersmay be disposed inside the fluid scrubber 122 adjacent the chevrons 170and may be operated periodically to spray clean water or a portion ofthe wastewater feed on the chevrons 170 to keep them clean.

Concentrated liquid also may be removed from the bottom of the fluidscrubber 122 via the exit port 173 and may be further processed ordisposed of in any suitable manner in a secondary re-circulating circuit181. In particular, the concentrated liquid removed by the exit port 173contains a certain amount of suspended solids, which preferably may beseparated from the liquid portion of the concentrated liquid and removedfrom the system using the secondary re-circulating circuit 181. Forexample, concentrated liquid removed from the exit port 173 may betransported through the secondary re-circulating circuit 181 to one ormore solid/liquid separating devices 183, such as settling tanks,vibrating screens, rotary vacuum filters, horizontal belt vacuumfilters, belt presses, filter presses, and/or hydro-cyclones. After thesuspended solids and liquid portion of the concentrated wastewater areseparated by the solid/liquid separating device 183, the liquid portionof the concentrated wastewater with suspended particles substantiallyremoved may be returned to the sump 172 for further processing in thefirst or primary re-circulating circuit connected to the concentrator.

The gas, which flows through and out of the fluid scrubber 122 with theliquid and suspended solids removed therefrom, exits out of piping orductwork at the back of the fluid scrubber 122 (downstream of thechevrons 170) and flows through an induced draft fan 190 of the outletassembly 124, where it may be recycled to a different process, orexhausted to the atmosphere in the form of the cooled hot inlet gasmixed with the evaporated water vapor. Of course, an induced draft fanmotor 192 is connected to and operates the fan 190 to create negativepressure within the fluid scrubber 122 so as to ultimately draw gasthrough the inlet assembly 119 and the concentrator assembly 120. Theinduced draft fan 190 needs only to provide a slight negative pressurewithin the fluid scrubber 122 to assure proper operation of theconcentrator 110.

While the speed of the induced draft fan 190 can be varied by a devicesuch as a variable frequency drive operated to create varying levels ofnegative pressure within the fluid scrubber 122 and thus can usually beoperated within a range of gas flow capacity to assure complete gas flowthrough the inlet assembly 119. If the gas flowing in through the inletassembly 119 is not of sufficient quantity, the operation of the induceddraft fan 190 cannot necessarily be adjusted to assure a proper pressuredrop across the fluid scrubber 122 itself. That is, to operateefficiently and properly, the gas flowing through the fluid scrubber 122must be at a sufficient (minimal) flow rate at the input of the fluidscrubber 122. Typically this requirement is controlled by keeping atleast a preset minimal pressure drop across the fluid scrubber 122.However, if at least a minimal level of gas is not flowing in throughthe inlet assembly 119, increasing the speed of the induced draft fan190 will not be able to create the required pressure drop across thefluid scrubber 122.

To compensate for this situation, the cross flow scrubber 122 mayoptionally be designed to include a gas re-circulating circuit which canbe used to assure that enough gas is present at the input of the fluidscrubber 122 to enable the system to acquire the needed pressure dropacross the fluid scrubber 122. In particular, the gas re-circulatingcircuit includes a gas return line or return duct 196 which connects thehigh pressure side of the outlet assembly 124 (e.g., downstream of theinduced draft fan 190) to the input of the fluid scrubber 122 (e.g., agas input of the fluid scrubber 122) and a baffle or control mechanism198 disposed in the return duct 196 which operates to open and close thereturn duct 196 to thereby fluidly connect the high pressure side of theoutlet assembly 124 to the input of the fluid scrubber 122. Duringoperation, when the gas entering into the fluid scrubber 122 is not ofsufficient quantity to obtain the minimal required pressure drop acrossthe fluid scrubber 122, the baffle 198 (which may be, for example, a gasvalve, a damper such as a louvered damper, etc.) is opened to direct gasfrom the high pressure side of the outlet assembly 124 (i.e., gas thathas traveled through the induced draft fan 190) back to the input of thefluid scrubber 122. This operation thereby provides a sufficientquantity of gas at the input of the fluid scrubber 122 to enable theoperation of the induced draft fan 190 to acquire the minimal requiredpressure drop across the fluid scrubber 122.

The combination of features illustrated in FIGS. 1-3 makes for a compactfluid concentrator 110 that uses exhaust heat, for example in the formof exhaust gas from a natural gas flare, which waste heat mightotherwise be vented directly to the atmosphere. Importantly, theconcentrator 110 uses only a minimal amount of expensive hightemperature resistant material to provide the piping and structuralequipment required to accommodate potentially high temperature gasesentering the concentrator via the inlet assembly 119. In fact, due tothe rapid cooling that takes place in the venturi section 162 of theconcentrator assembly 120, the venturi section 162, the flooded elbow164 and the fluid scrubber 122 are typically cool enough to touchwithout harm (even when the gases exiting the exhaust stack 130 are at1800 degrees Fahrenheit). Rapid cooling of the gas-liquid mixture allowsthe use of generally lower cost materials that are easier to fabricateand that are corrosion resistant. Moreover, parts downstream of theflooded elbow 164, such as the fluid scrubber 122, induced draft fan190, and exhaust section 124 may be fabricated from materials such asfiberglass.

The fluid concentrator 110 is also a very fast-acting concentrator.Because the concentrator 110 is a direct contact type of concentrator,it is not subject to deposit buildup, clogging and fouling to the sameextent as most other concentrators.

Moreover, in some embodiments, due to the compact configuration of theinlet assembly 119, the concentrator assembly 120 and the fluid scrubber122, parts of the concentrator assembly 120, the fluid scrubber 122, thedraft fan 190 and at least a lower portion of the exhaust section 124can be permanently mounted on (connected to and supported by) a skid orplate 230, as illustrated in FIG. 1. The upper parts of the concentratorassembly 120 and/or the inlet assembly 119 may be removed and stored onthe skid or plate 230 for transport, or may be transported in a separatetruck. Because of the manner in which the lower portions of theconcentrator 110 can be mounted to a skid or plate, the concentrator 110is easy to move and install. In particular, during set up of theconcentrator 110, the skid 230, with the fluid scrubber 122, the floodedelbow 164 and the draft fan 190 mounted thereon, may be offloaded at thesite at which the concentrator 110 is to be used by simply offloadingthe skid 230 onto the ground or other containment area at which theconcentrator 110 is to be assembled. Thereafter, the venturi section162, the quencher 159, and the inlet assembly 119 may be placed on topof and attached to the flooded elbow 164. In other embodiments, theconcentrator 110 can be part of a larger scale, permanent installation(e.g., not necessarily mounted on a moveable skid or plate).

Because most of the pumps, fluid lines, sensors and electronic equipmentare disposed on or are connected to the fluid concentrator assembly 120,the fluid scrubber 122 or the draft fan assembly 190 (e.g., in acompact, skid-mounted embodiment), setup of the concentrator 110 at aparticular site requires only minimal plumbing, mechanical, andelectrical work at the site. As a result, the concentrator 110 isrelatively easy to install and to set up at (and to disassemble andremove from) a particular site. Moreover, because a majority of thecomponents of the concentrator 110 are permanently mounted to the skid230, the concentrator 110 can be easily transported on a truck or otherdelivery vehicle and can be easily dropped off and installed atparticular location, such as next to an gas flare at a natural gas well,next to a landfill exhaust stack, or at a power plant to concentrate FGDwastewater.

FIG. 3 illustrates a schematic diagram of a control system 300 that maybe used to operate the concentrator 110. As illustrated in FIG. 3, thecontrol system 300 includes a controller 302, which may be a form ofdigital signal processor type of controller, a programmable logiccontroller (PLC) which may run, for example, ladder logic based control,or any other type of controller. The controller 302 is, of course,connected to various components within the concentrator 110, for exampleas described below.

For instance, the controller 302 may be connected to and control theambient air inlet valve 306 disposed in the inlet assembly 119 of FIG. 1upstream of the venturi section 162 and may be used to control the pumps182 and 184 which control the amount of and the ratio of the injectionof new liquid to be treated and the re-circulating liquid being treatedwithin the concentrator 110. The controller 302 may be operativelyconnected to a sump level sensor 317 (e.g., a float sensor, anon-contact sensor such as a radar or sonic unit, or a differentialpressure cell). The controller 302 may use a signal from the sump levelsensor 317 to control the pumps 182 and 184 to maintain the level ofconcentrated fluid within the sump 172 at a predetermined or desiredlevel. Also, the controller 302 may be connected to the induced draftfan 190 to control the operation of the fan 190, which may be a singlespeed fan, a variable speed fan or a continuously controllable speedfan. In one embodiment, the induced draft fan 190 is driven by avariable frequency motor, so that the frequency of the motor is changedto control the speed of the fan. Moreover, the controller 302 may beconnected to a temperature sensor 308 disposed at, for example, theinlet of the concentrator assembly 120 or at the inlet of the venturisection 162, and receive a temperature signal generated by thetemperature sensor 308. The temperature sensor 308 may alternatively belocated downstream of the venturi section 162 or the temperature sensor308 may include a pressure sensor for generating a pressure signal.

In any event, as illustrated in FIG. 3, the controller 302 may also beconnected to a motor 310 which drives or controls the position of theventuri plate 163 within the narrowed portion of the concentratorassembly 120 to control the amount of turbulence caused within theconcentrator assembly 120. Still further, the controller 302 may controlthe operation of the pumps 182 and 184 to control the rate at which (andthe ratio at which) the pumps 182 and 184 provide re-circulating liquidand new waste fluid to be treated to the inputs of the quencher 159 andthe venturi section 162. In one embodiment, the controller 302 maycontrol the ratio of the re-circulating fluid to new fluid to be about10:1, so that if the pump 184 is providing 8 gallons per minute of newliquid to the input 160, the re-circulating pump 182 is pumping 80gallons per minute. Additionally, or alternatively, the controller 302may control the flow of new liquid to be processed into the concentrator(via the pump 184) by maintaining a constant or predetermined level ofconcentrated liquid in the sump 172 using, for example, the level sensor317. Of course, the amount of liquid in the sump 172 will be dependenton the rate of concentration in the concentrator, the rate at whichconcentrated liquid is pumped from or otherwise exists the sump 172 viathe secondary re-circulating circuit and the rate at which liquid fromthe secondary re-circulating circuit is provided back to the sump 172,as well as the rate at which the pump 182 pumps liquid from the sump 172for delivery to the concentrator via the primary re-circulating circuit.

Furthermore, as illustrated in the FIG. 3, the controller 302 may beconnected to the venturi plate motor 310 or other actuator which movesor actuates the angle at which the venturi plate 163 is disposed withinthe venturi section 162. Using the motor 310, the controller 302 maychange the angle of the venturi plate 163 to alter the gas flow throughthe concentrator assembly 120, thereby changing the nature of theturbulent flow of the gas through concentrator assembly 120, which mayprovide for better mixing of the and liquid and gas therein and obtainbetter or more complete evaporation of the liquid. In this case, thecontroller 302 may operate the speed of the pumps 182 and 184 inconjunction with the operation of the venturi plate 163 to provide foroptimal concentration of the wastewater being treated. Thus, thecontroller 302 may coordinate the position of the venturi plate 163 withthe operation of the exhaust stack cap 134, the position of the ambientair or bleed valve 306, and the speed of the induction fan 190 tomaximize wastewater concentration (turbulent mixing) without fullydrying the wastewater so as to prevent formation of dry particulates.The controller 302 may use pressure inputs from the pressure sensors toposition the venturi plate 163. Of course, the venturi plate 163 may bemanually controlled or automatically controlled.

The controller 302 may also be connected to a motor 312 which controlsthe operation of the damper 198 in the gas re-circulating circuit of thefluid scrubber 122. The controller 302 may cause the motor 312 or othertype of actuator to move the damper 198 from a closed position to anopen or to a partially open position based on, for example, signals frompressure sensors 313, 315 disposed at the gas entrance and the gas exitof the fluid scrubber 122. The controller 302 may control the damper 198to force gas from the high pressure side of the exhaust section 124(downstream of the induced draft fan 190) into the fluid scrubberentrance to maintain a predetermined minimum pressure difference betweenthe two pressure sensors 313, 315. Maintaining this minimum pressuredifference assures proper operation of the fluid scrubber 122. Ofcourse, the damper 198 may be manually controlled instead or in additionto being electrically controlled.

The controller 302 may implement one or more on/off control loops usedto start up or shut down the concentrator 110. For example, thecontroller 302 may implement an induced draft fan control loop whichstarts or stops the induced draft fan 190 based on whether theconcentrator 110 is being started or stopped. Moreover, duringoperation, the controller 302 may implement one or more on-line controlloops which may control various elements of the concentrator 110individually or in conjunction with one another to provide for better oroptimal concentration. When implementing these on-line control loops,the controller 302 may control the speed of induced draft fan 190, theposition or angle of the venturi plate 163, and/or the position of theambient air valve 306 to control the fluid flow through the concentrator110, and/or the temperature of the air at the inlet of the concentratorassembly 120 based on signals from the temperature and pressure sensors.Moreover, the controller 302 may maintain the performance of theconcentration process at steady-state conditions by controlling thepumps 184 and 182 which pump new and re-circulating fluid to beconcentrated into the concentrator assembly 120. Still further, thecontroller 302 may implement a pressure control loop to control theposition of the damper 198 to assure proper operation of the fluidscrubber 122. Of course, while the controller 302 is illustrated in FIG.3 as a single controller device that implements these various controlloops, the controller 302 could be implemented as multiple differentcontrol devices by, for example, using multiple different PLCs.

Referring again to FIG. 1, the concentrator section 120 may include areagent inlet 187 that is connected to a supply of reagent material 193(e.g., a pH-adjusting agent such as an alkaline agent) by a supply line189. A pump 191 may pressurize the supply line 189 with reagent materialfrom the supply of reagent material 193 so that the reagent material isinjected into the concentrator section 120 (e.g., proximate the venturi162) to mix with the exhaust gas from the exhaust stack 130 orgenerator. In other embodiments, the reagent material may be mixed withthe flue gas desulfurization water in the wastewater input line 186prior to being delivered to the concentrator section 120. Regardless,once the reagent material is delivered to the concentrator section 120,the reagent material rapidly mixes with the exhaust gas in theconcentrator section 120 along with the wastewater, as described above.As illustrated in FIG. 3, the controller 302 may be operativelyconnected to the pump 191 to control the rate at which reagent materialis metered into the concentrator section 120. The controller 302 maydetermine a proper metering rate for the reagent based. Thus, thedisclosed concentrator is readily adaptable to variations in exhaust gascomponents and/or differing mass flow rates of the exhaust gas. As aresult, the disclosed concentrator is capable of simultaneouslyconcentrating flue gas desulfurization water and removing pollutantsfrom the same.

Generally, liquid concentrated in the concentrator 110 will eventuallyreach a state where the concentrate is saturated with dissolved solids.Concentration beyond this point will cause some of the dissolved solidsto precipitate out of the solution as suspended solids. The point ofsaturation will depend on the types of dissolved solids in thewastewater. The suspended solids are kept in suspension in theconcentrator 110 due to the mixing action created therein. However, itmay be desirable to extract these suspended solids and to dispose of thesuspended solids in a landfill or otherwise. The suspended solids may beextracted from the settling tank 183 and may optionally be stabilized,for example by mixing with Portland cement, prior to disposal in alandfill.

Often, natural well operations (and drilling) require heavy waters(known as drilling muds) to aid in drilling and extraction operations.Usually, these heavy waters are created by dissolving heavy solublesalts (such as salts including Barium and other heavy elements) withwater to create water that weighs 10 lb/gal or more (known in theindustry as 10 lb brine water). This method of manufacturing heavy brinewaters for drilling is expensive because the heavy salts are expensive.Generally, drilling operations desire waters that are as heavy aspossible because heavier waters improve drilling and extractingoperations.

The concentrator 110 described above has been found to have thecapability to manufacture heavy brine waters for the drilling industry.In some cases, the concentrator 110 may be used to manufacture heavybrine waters in excess of 12 lb/gal or more, which are highly desirablein the drilling industry. The inventors have discovered that bymodifying the settling tank 183 (FIG. 1) with a mixing system, theconcentrator 110 is capable of manufacturing custom heavy brine watersto suit a customer's specifications.

Turing now to FIG. 4, a mixing system 500 for creating custom heavybrine waters is illustrated. The mixing system 500 includes the settlingtank 183 of the concentrator 110, and a processor/controller 510.

When concentrated liquid is sent to the settling tank 183 from the sump172 (FIG. 1), and the concentrated liquid is allowed to sit quietly inthe settling tank 183, eventually suspended solids will be drawn to thebottom of the settling tank 183 via gravity and liquid saturated withdissolved solids will rise to the top of the settling tank 183 due tothe differences in weights between the two. This phenomenon results ingenerally two regions within the settling tank 183. The first region isthe top region or saturated liquid region 512 and the second region isthe bottom region or the settled solids region 514. The weight of theliquid in the saturated liquid region 512 is generally less than theweight of an identical volume of settled solids from the settled solidsregion 514. For example, depending upon the dissolved solids in thewastewater to begin with, the weight of the saturated liquid may bebetween 9 lb/gal and 11 lb/gal, while the weight of the settled solidsmay be between 12 lb/gal and 14 lb/gal.

By mixing desired ratios of the saturated liquid with the settledsolids, brines of custom weights may be manufactured to suit the needsof the drilling industry. For example, if the weight of the saturatedliquid is 10 lb/gal and the weight of the settled solids is 12 lb/gal,and if a customer desires a custom brine having a weight of 11 lb/gal,then equal amounts of the saturated liquid and the settled solids may bemixed to create a brine with a weight of 11 lb/gal. The disclosed mixingsystem 500 performs this function.

In addition to the settling tank 183 and the controller/processor 510,the mixing system 500 includes a saturated liquid extraction port 520and a settled solids extraction port 522. The saturated liquidextraction port 520 is located in the upper half or the settling tank183, above a solid/liquid separation line 526. The saturated liquidextraction port 520 is connected to a saturated liquid line 530. Asaturated liquid valve 532 is located within the saturated liquid line530 and the saturated liquid valve 532 controls the flow of saturatedliquid through the saturated liquid line 530. Similarly, the settledsolids extraction port 522 is connected to a saturated solids line 534.A settled solids valve 536 is located within the settled solids line 534and the settled solids valve 536 controls the flow of settled solidsthrough the settled solids line 534. The controller/processor 510 may beoperatively connected to the saturated liquid valve 532 and to thesettled solids valve 536. The controller/processor 510 controls thesaturated liquid valve 532 and the settled solids valve 536 to controlthe ratio of saturated liquid to settled solids to achieve a mixture ofthe two having a desired weight.

The mixing system 500 may optionally include a means for injecting alubricant or suspension agent into the mixture of saturated liquid andsettled solids to keep the settled solids in suspension in the mixture.For example, the mixing system 500 may include a source oflubricant/suspension agent 550 that is connected to a mixture line 552downstream of the junction of the saturated liquid line 530 and thesettled solids line 534. The processor/controller 510 may be operativelyconnected to the source of lubricant/suspension agent 550 toperiodically, or continuously, dose the mixture withlubricant/suspension agent to assist in keeping the settled solids insuspension.

The processor/controller 510 may also be operatively connected to aweight sensor 560, located in the mixture line 554 so that thecontroller/processor 510 has a feedback mechanism to adjust amounts ofthe saturated liquid and the settled solids to achieve the desiredmixture weight. Furthermore, the controller/processor 510 may beoperatively connected to a saturated liquid sensor 562 and to a settledsolids sensor 564 to monitor the weights of the saturated liquid and thesettled solids to account for changes in the makeup of wastewater beingconcentrated and thus the weights of the saturated liquid and thesettled solids.

While certain representative embodiments and details have been shown forpurposes of illustrating the invention, it will be apparent to thoseskilled in the art that various changes in the methods and apparatusdisclosed herein may be made without departing from the scope of theinvention.

1. A liquid concentrator system, comprising: a concentrator sectionincluding; a gas inlet, a gas outlet, a mixing corridor disposed betweenthe gas inlet and the gas outlet, the mixing corridor having a narrowedportion in which gas flow within the mixing corridor accelerates whentraveling from the gas inlet to the gas outlet; a liquid inlet throughwhich liquid to be concentrated is injected into the mixing corridor,the liquid inlet disposed in the mixing corridor between the gas inletand the narrowed portion; a demister disposed downstream of theconcentrator section, the demister including a demister gas flow passagecoupled to the gas outlet of the concentrator section, a liquidcollector disposed in the demister gas flow passage to remove liquidfrom gas flowing in the demister gas flow passage, and a reservoir thatcollects the liquid removed from the gas flowing in the demister gasflow passage by the liquid collector; a re-circulating circuit disposedbetween reservoir and the mixing corridor to transport liquid within thereservoir to the mixing corridor; and a secondary re-circulating circuitincluding a settling tank to separate saturated liquid and suspendedsolids; and a custom brine mixing device operatively coupled to thesettling tank.
 2. The liquid concentrator system of claim 1, wherein thecustom brine mixing device includes a saturated liquid extraction port,a saturated liquid valve operatively coupled to the saturated liquidextraction port, a settled solids extraction port, a settled solidsvalve operatively coupled to the settled solids extraction port, and acontroller operatively coupled to the saturated liquid valve and to thesettled solids valve.
 3. The liquid concentrator system of claim 2,wherein the custom brine mixing device includes a source of lubricantthat is fluidly connected to a mixture line downstream of a point atwhich the saturated liquids and settled solids are mixed.
 4. The liquidconcentrator system of claim 3, wherein the controller is operativelycoupled to a mixture weight sensor, to a saturated liquid weight sensor,and to a settled solids weight sensor.
 5. The liquid concentrator systemof claim 1, wherein the concentrator section includes an adjustable flowrestriction disposed in the narrowed portion of the mixing corridor, theflow restriction adjustable to alter gas flow through the mixingcorridor.
 6. The liquid concentrator system of claim 5, wherein theadjustable flow restriction is a venturi plate that is adjustable tochange the size or shape of the narrowed portion of the mixing corridor.7. A method of making custom brines, the method comprising:concentrating a liquid by evaporating a portion of water in the liquidto produce a partially concentrated liquid; sending the partiallyconcentrated liquid to a settling tank; drawing suspended solids to thebottom of the settling tank to produce a settled solid portion in afirst region of the settling tank while leaving dissolved solids insaturated liquid portion in a second region of the settling tank;drawing a portion of the suspended solids from the first region; drawinga portion of the saturated liquid from the second region; and mixing thesuspended solids and the saturated liquid to form a custom brinemixture.
 8. The method of claim 7, further comprising: injecting alubricant into the custom brine mixture.
 9. The method of claim 7,further comprising measuring the weight of the custom brine mixture. 10.The method of claim 9, further comprising measuring the weight of thesaturated liquid.
 11. The method of claim 10, further comprisingmeasuring the weight of the settled solids.
 12. The method of claim 11,further comprising adjusting relative amounts of the saturated liquidand the settled solids to adjust the weight of the custom brine mixture.13. The method of claim 7, wherein the liquid is concentrated in aconcentrator including a gas inlet, a gas outlet, a mixing corridordisposed between the gas inlet and the gas outlet, the mixing corridorhaving a narrowed portion in which gas flow within the mixing corridoraccelerates when traveling from the gas inlet to the gas outlet, ademister disposed downstream of the concentrator section, the demisterincluding a demister gas flow passage coupled to the gas outlet of theconcentrator section, and a liquid collector disposed in the demistergas flow passage to remove liquid from gas flowing in the demister gasflow passage.